JPS59209332A - Dental total jaw x-ray electrophotographic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the field of dental full-mouth X-ray photography, and more particularly to a dental full-mouth X41 electrophotographic device that utilizes reverse field electrophotography in a dental full-mouth X-ray device. .

X-ray electrophotography has also been used for medical diagnosis.
Although the disadvantage was that the X-ray exposure dose had to be increased to 0.2 to compensate for the lack of sensitivity, it did not use expensive silver compared to conventional silver halide film. In addition, various techniques have been developed for various reasons, including the fact that images with enhanced image edges are obtained due to a phenomenon unique to electrophotography called the edge effect, and are effective for diagnosis. Among them, the method and device called xeroradiography developed by Xerox is a new X-ray image recording device that applies electrophotographic technology. It records a latent image and then develops it with a charged powder called toner to record the image on special paper.It has been used for X-ray diagnosis of soft tissues, especially mammary glands, and has recently been used. This is particularly the focus of attention in Japan, where the incidence of breast cancer is increasing.

However, the biggest drawback of this device is that
It was necessary to increase the radiation exposure dose to obtain the necessary sensitivity. Therefore, since 1970, research has been carried out on highly sensitive X-ray electrophotography technology, and in recent years a method called the double charging method, which effectively utilizes the luminescence of fluorophores due to X-ray stimulation and uses a reversing electric field, has been developed. It has been developed. X-ray electrophotography equipment using this method in the general medical field has already been used for simple
Although it is being put into practical use only in the field of radiography, it has not yet been put into practical use in full-mouth dental X-ray imaging devices.

In view of the description, the present invention is suitable for full-jaw X@ photography and this X-ray electrophotography? The purpose is to provide a device that makes this possible. According to the device of the present invention, a general X-ray imaging device using a silver halide photographic photosensitive plate made in the United States, that is, a narrow X-ray beam focused by a vertically long slit-shaped opening provided in an X-ray shielding plate is transmitted to a new The structure itself is such that the photosensitive surface is sequentially irradiated, and the silver salt photosensitive plate is replaced with an X-ray electrophotographic photosensitive plate that has been charged in advance with a corona discharger. By applying a reverse electric field to the photosensitive plate, the sensitivity of the image is improved and the exposure dose is reduced as much as possible. The background to the completion of the present invention is, for example, a mechanism for continuously moving a flat film holder (Utility Model Registration No. 1439179 developed by the present applicant), and a photosensitive plate for X-ray electrophotography that is generally flat. This allows for continuous feeding. As a further development of the present invention, the present applicant has developed a device in which a photosensitive plate for ordinary silver halide film and a photosensitive plate for X-ray electrophotography can be interchangeably attached to one film holder. Application No. 57-16866 (filed on February 8, 1982)
There are some that apply

Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, the number 1 in the longitudinal direction indicates a rotating arm (indicated by a dashed line) whose center portion is fixed from above by a rotating shaft (not shown) and suspended by it, and is used for X-ray imaging to be described later. Sometimes, as the rotation axis rotates, the camera rotates in the direction of arrow A on a specific plane, usually on a horizontal plane, while drawing a curved trajectory that approximates the dental arch of subject C (patient P). The subject P is located below the rotating arm 1, and the portion to be photographed (dental arch) is located almost directly below the pivot axis. A photosensitive plate holder 2 for X-ray electrophotography and an X-ray source 3 are attached to both ends of the rotating shaft 1, facing downward, so that the X-ray irradiation port of the X-ray source 3 and the photosensitive plate holder 2 The subject P is located on a line connecting the X-ray incident part of On the front surface of the X-ray photosensitive plate holder 2, that is, on the subject side, an X-ray shielding plate 6 made of an X-ray shielding material is fixedly arranged with respect to the rotating arm 1. 6 X-ray shielding plates,
It has a slit-shaped opening 5 extending in a direction substantially perpendicular to the rotation specific plane of the rotating arm 1, and the width of the opening 50 allows the X-rays emitted from the X-ray source 3 and reaching the photosensitive plate 4 to be Regulate the projection width. X-ray photosensitive plate holder 2 is
The photosensitive plate 4 can be detachably attached, and when attached, it is fixed by appropriate means. The photosensitive plate holder 2 is supported by a supporting means and a feeding mechanism, which will be described later, so as to move linearly in a direction parallel to the rotation specific plane of the rotation arm 1, and in synchronization with the rotation of the rotation arm 1. In synchronization with the movement of the X-ray source 3, the rotary arm 10 moves at a predetermined relative speed in the direction of arrow B (direction C, which is substantially perpendicular to the X-ray incident angle and opposite to the rotational direction A). Simultaneously with this movement, the X-ray image emitted from the X-ray source P and transmitted through the subject P is transmitted to the X-ray shielding plate 6.
The X-ray section 1e of the dental arch of the subject P is projected onto the moving photosensitive plate 4.
Photography will take place.

The structure of the X-ray photosensitive plate 4 is, for example, as shown in FIG.
), a support plate 41 made of an X-ray transparent material such as , a phosphor layer 42 for emitting X-ray fluorescence made of a material such as Cd, O, S, a transparent electrode layer 43 , a lower transparent insulating layer 44 A photoconductor layer 4 made of a material such as .5e-4'e.
5 and a surface insulating layer 46 are sequentially laminated and integrated. Also, depending on the X-ray sensitivity of the photoconductor layer 45,
It is possible to omit the phosphor layer 45, in which case the electrogenic layer 43 and the lower gIK insulating layer 44 need not be transparent. An electrostatic latent image by X-rays is formed on this X-ray photosensitive plate 4 according to the following process. In the first step, before or after assembling the photosensitive plate 4 into the photosensitive plate holder 2, the photosensitive plate 4 is charged with a suitable external discharge means, such as a corona discharger (not shown).
Therefore, the insulation N46 is uniformly charged to a specific polarity.

The polarity is desirably selected so that the surface of the surface insulating layer 46 is charged with charges fT of the same polarity as the majority carriers of the photoconductor layer 45. In the following, for convenience of explanation, a positive corona discharge will be used. If this has been done, please write h. Due to the corona discharge, the majority carriers in the photoconductor layer 45 of the photosensitive plate 4 migrate within the photoconductor layer according to the electric field and reach near the interface with the lower insulating layer, and soon most of them are transferred to the photoconductor layer. The layer trap is captured and sustains internal polarization C below P,
1. (abbreviated as P) causes the formation of a P charge layer. Such a state is shown in FIG. 3 (Jl), in which four charged photosensitive plates 41 are placed on the photosensitive plate holder 2 so that the X@ irradiation side is rotated.

In the second process, as shown in FIG. 3(b), an X-ray image is formed on the photosensitive plate 4 while scanning the photosensitive plate 4 in the direction of arrow B according to the photosensitive plate holder 2 in synchronization with the rotation of the rotating arm 1. At the same time, a uniform direct current electric field (C or alternating current) of negative polarity is applied to the photosensitive plate 4 to form an electrostatic latent image thereon in accordance with the amount of X-rays. In this example, the application of the electric field is
h on the back side of the photosensitive plate holder 2, that is, on the opposite side from the subject P.
A discharge electrode 7 provided close to the photoreceptor holder 2
It is carried out by The electrode 7 is made of, for example, corona discharge means, and is arranged to sandwich the photosensitive plate 4, facing the slit-shaped opening 5 of the X-ray shielding plate 6, and extending parallel to the longitudinal direction of the opening 5. The surface insulating layer 46 of the photosensitive plate 4
A negative electric field is applied from the side (ie, a reverse electric field is applied). At the fc portion of the photosensitive plate onto which the X-rays are projected, the X-rays pass through the support plate 41 and excite the phosphor layer 42, thereby causing the layer 42 to generate visible light. This visible light contributes significantly to the excitation of the photoconductor layer 45, and at the same time a portion of the projected X@ also acts to directly cause such excitation. The excitation of the photoconductor layer causes the p, 1. Most of the p charges are released and a large number of free charges are generated within the photoconductor layer. As a result, most of the applied charge is concentrated on the surface insulating layer 46, so that the surface charge charged in the first process is resupplied and dissipated, and at the same time new polarity, that is, negative polarity charge is generated. layer 46 is charged.

On the other hand, for areas that are not exposed to X-rays, P.

1. Since the P charge is not rapidly released, the surface charge charged in the first process is difficult to disappear, and the positive charge remains. Thus X,
An electrostatic latent image is formed that corresponds to the line image.

An applied voltage of several thousand volts is desirable for both the first and second stages of corona discharge, - for example, positive corona discharge of 6,000
V, the negative corona discharge is -7,000 OOV.

The electrostatic latent image obtained as described above is processed by known means.
A permanent recorded image is formed by developing with a charged powder called toner, then transferring it onto a suitable support such as paper or an insulating film, and fixing it.

4 and 5 show the photosensitive plate holder 2 and its feeding mechanism M applicable to the present invention. The photosensitive plate holder 2 includes a body 20, a channel-shaped receiver provided close to the surface where the slit opening 5 of the shielding plate 6 is formed, and a pair of receivers fixed to the back surface of the body 20 at both ends of the body 20. A support member 50 (only one of which is shown), a rectangular bar-shaped slider 10 extending linearly and in parallel with its ends fixed to both support members 50 and a frame passing between the two members, and a plate-shaped slide par 10. The slider 12 is supported movably in a direction parallel to the specific rotation plane of the arm 1 by engaging with a slide bearing device (for example, Accuride) 51 fixed to the rotation arm 1. n is there. Uke is body 2
0 has a flat holding part 20M and a locking edge part 21 formed by bending in a dogleg shape in opposite directions at the upper and lower edges of the part 20&, and these parts zoa and zi allow the receiver to form a groove. 23, the receiver opens the end opening/closing door 24 of the photosensitive plate holder 2 along the groove 23, that is, as seen in FIG.
The photosensitive plate 4 can be inserted and removed. In addition to the aforementioned photosensitive plate for X-ray electrophotography, a general photosensitive plate for silver salt photography can be used as the photosensitive plate, and the details of such a configuration are described in the actual application by one of the applicants of the present application. It is described in the specification and drawings of No. 16866/1983 (filed on February 8, 1982). The holding portion 20m is at least X of the photosensitive plate 4.
The portion facing the line irradiation portion is an opening 13, through which the photosensitive plate is subjected to electric discharge by the above-mentioned discharge electrode 7. Note that reference numeral 8 is a power supply device electrically connected to the electrode 7, and applies an appropriate voltage to the electrode 7 only during X-ray imaging. The discharge electrode 7 is fixed to the protrusion 15 of the swing arm 1 by an electrode support member 14 . Also,
A light shielding plate 16 is provided on the electrode support member 14 to prevent light from entering through the elongated opening 17 on the back side of the photosensitive plate holder 2. Reference numeral 9 indicates a variable speed motor fixed to the swing frame 53, and a rotor 11 is fixed to the motor shaft 54, which intersects and engages one surface of the slider 10 in a perpendicular direction. . The frame 53 is swingably supported by a pin 56 with respect to a bracket 55 fixed to the arm 1, and is supported by a tension spring 56 stretched between the frame 53 and the arm 1 as seen in FIG. It is biased so that it always moves counterclockwise. As a result, the trochanter 11 is brought into pressure contact with the slide par 10 by an appropriate frictional force. The variable speed motor 9 rotates the rotor 11 at a speed synchronized with the moving speed of the X@power source under the control of a control means (not shown).

In the above configuration, when the rotor 9 is driven following the rotation of the arm 1, the trochanter 11 rolls against the slider 10, and the rolling friction force at that time causes the slider 10, and therefore the photosensitive plate holder. 2 and photoreceptor 4 move in the direction of arrow B in FIG. Although such a feeder tank has a simple structure and has little vibration during driving, it is possible to obtain flawless photographs; however, the present invention is not limited thereto. It not only eliminates the need to use expensive silver compared to photographing with a salt photographic plate, and eliminates the problem of pollution caused by the treatment of silver compounds discharged during the development of a silver salt photographic plate. It is possible to apply electron X-ray photography to the field of dental full-mouth X-ray photography, which has a low radiation exposure dose.Moreover, it is possible to obtain an image effect called the edge effect, which is unique to electronic X-ray photography. In particular, it is possible to clearly image malignant tumors that occur around the jawbone and soft tissue tumors that occur under the skin and deep within the jawbone, which could not be sufficiently captured with regular dental full-mouth X-ray equipment. It is valid.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing an X-ray electrophotography neck according to the present invention, FIG. 2 is an enlarged cross-sectional view of a part of the apparatus shown in FIG. 1, and FIG. ) is an explanatory diagram illustrating changes in the charge distribution of the portion shown in FIG. 2, FIG. 4 #- is a partially cutaway side view of the device portion shown in FIG. It is a perspective view of the part shown in the figure. (Explanation of symbols) 1.--swivel arm, 2.--X-ray photosensitive plate holder, 3.--
X-ray source, 4--X-ray photosensitive plate, 5... slit-shaped opening,
6--X-ray shielding plate, 7--discharge electrode, 41--support plate, 42--fluorescent layer, 43--electrode, 44-lower insulating layer, 45--photoconductive layer, 46- ...Surface insulation layer. - Above - Applicant's agent Patent attorney Hidehiko Matsuno Figure 3 (a) Figure 3 (b) Figure 4 1U 1'/

Claims (1)

[Scope of Claims] L: A rotating arm that holds an object between each other and has an X-ray source at one end and a photosensitive plate holder for X-ray electrophotography at the other end in the same relationship with each other, and rotates on a specific plane, and the holder an X-ray shielding plate having a slit-like opening for X-ray incidence that is located on the subject side, is fixed to the arm, and extends in a direction intersecting the specific plane; a photosensitive plate for X-ray electrophotography that is electrically charged;
It consists of a discharge electrode that applies a DC electric field or an AC electric field having a polarity opposite to the specific polarity to the photosensitive plate, and while moving the holder in synchronization with the rotation of the arm, the Focusing X through the object and the aperture
A dental full-mouth X-ray electrophotographic apparatus, characterized in that a line beam is sequentially irradiated onto the photosensitive plate, and at the same time, the electric field is applied to the photosensitive plate by the discharge electrode. 2. The photosensitive plate holder is a channel type consisting of a flat holding part and a pair of locking edge parts provided at both ends of the holding part, and the receiver for the photosensitive plate forms a groove on the front surface of the holding part. The Ω device according to claim 1, wherein the receiver has a photosensitive plate for X-ray silver salt photography and a photosensitive plate for X-ray electrophotography attached in the groove so as to be replaceable and non-removable. .